Transform any sequence pair to primer pairs

Primer-BLAST, included in UGENE-7921, could BLAST only primers, which are produced by Primer3. Sometimes, user could have primers, which he's got from some external sources:

In this case, primer pair is not defined as a fit primer pair to be BLASTed. 

The best solution here is to select primers you want to blast, click some button and make copyes of them in a "top_primer" annotations table (default annotation table for primer pairs).

Scenario:

1. Open _common_data\primer3\custom_primers.gb.
2. Select "primer1" and "primer2" annotations.
3. Click right mouse button -> Edit -> Transform into a primer pair.
   Expected: new primer pair has appeared.